PROJECT SUMMARY/ABSTRACT Substance use (SU), including hazardous alcohol use, is common among women with HIV in the United States (US) and rates exceed those of the general female population. Substance-using women with HIV are less likely to initiate and adhere to antiretroviral medications, which has important implications for morbidity, mortality, and HIV transmission. Drug and alcohol treatment mitigates these effects, but is underutilized. In addition, high-dose opioid pain therapy is prevalent among people with HIV, increasing their risk of prescription drug misuse. Marijuana may serve as an alternative for opioid-based pain management, but marijuana's effect on HIV clinical outcomes is unclear. Several policy initiatives have the potential to influence SU and drug and alcohol treatment in the US by: 1) curbing inappropriate prescribing practices for pain management (e.g., prescription drug monitoring programs [PDMPs]); 2) increasing access to drug and alcohol treatment (e.g., health parity laws [HPLs]); and 3) legalizing marijuana use for medical purposes (e.g., medical marijuana laws [MMLs]). Yet, little is known about how these health policies impact women with HIV. Studies suggest that these policies have benefits (e.g., HPLs associated with drug treatment). Others found negative or unintended consequences (e.g., MMLs associated with more alcohol, but less opioid use). This K01 leverages participant- level data from the NIH-funded Women's Interagency HIV Study by integrating cohort data with contextual data (e.g., Prescription Drug Abuse Policy System) capturing the policy and health care access environments where these women live. The proposed study will use a longitudinal, multilevel design to generate evidence on how health policies impact SU and drug and alcohol treatment among women with and without HIV in the US, and elucidate the pathways through which health policies shape HIV viral suppression among women with HIV. The specific aims are: Aim 1. Assess relationships between PDMPs and prescribed and non-prescribed opioid use over time, examining the modifying role of HIV status and race. Aim 2. Assess relationships between HPLs, access to drug and alcohol treatment, and treatment utilization over time, examining the modifying role of HIV status, health insurance, and patterns of SU. Aim 3: Assess relationships between MMLs, access to legalized marijuana, and marijuana use and hazardous drinking, examining the modifying role of HIV status and patterns of SU. Aim 4: Among women with HIV, assess the impact of PDMPS, HPLs, and MMLs on HIV viral suppression, examining the mediating or modifying role of SU and drug and alcohol treatment. To accomplish these aims the applicant will receive training in: 1) the epidemiology of SU, 2) empirical policy analysis, and 3) advanced longitudinal multilevel analysis, under the direction of University of North Carolina at Chapel Hill faculty Drs. Vivian Go, Adaora Adimora, Mark Holmes, and Daniel Bauer. These analyses will to inform future policy and structural interventions by generating causal evidence on how policies influence SU and alcohol and drug treatment over time among US women with and at risk of HIV.